1. Field of the Invention
The present invention relates to an ozone storage method and an ozone storage apparatus. Further, it relates to an ozone storage method and apparatus for storing ozone and extracting ozone by adsorption when it is demanded.
2. Discussion of the Related Art
In recent years, people have been very concerned about the environment. They are primarily concerned about water which has an intimate relation to their life.
Harmful chemicals such as some types of organic matter, ammonia, and so on, and other types of matter which may cause odors and colors are contained in secondary sewage treatment water, secondary night soil treatment water, industrial waste water, tap water, small water supply system water, exclusive tap water, water for industrial use, wastewater recycling system water, and effluents from fish farms and culture ponds. Further, organic matter such as environmental hormones are sometimes included and these elements are difficult to decompose through regular water treatments.
Accordingly, it is necessary to treat water thoroughly. Various water treatment methods have been investigated. Ozonolysis is a known decomposing method for decomposing organic matter such as environmental hormones.
Ozone is an oxidizer that is easy to use, and since it decomposes into oxygen, the concerns about secondary pollution are reduced. Therefore it is widely used for sterilizing, cleansing and oxidizing. However, ozone typically cannot be stored in cylinders or other containers since ozone, as a general rule, easily decomposes. Therefore, a silent discharge ozone generator, an ozone generator using an ultra-violet lamp or an electrolytic ozone generator is placed near the water treatment apparatus. The ozone generator is used to generate ozone that is directly used by the water treatment apparatus. However, with this method it is difficult to produce ozone to match a change in the required amount of ozone. Also, this method requires a great deal of electric power to generate the ozone.
The conventional ozone absorption/desorption operation will be explained below.
Japanese laid-open patent publication no. 11-292512 and other references disclose a conventional ozone storing technique. In this technique, ozone is absorbed for storage by an absorbent when the absorbent is cooled to a temperature not higher than xe2x88x9230xc2x0 C. by a cooling means and the compressed ozone is supplied to the absorbent. When desorbing ozone from the absorbent, the absorbent then needs to be heated and decompressed.
This means that when the absorbent absorbs ozone, it is compressed up to 5 atm and when the ozone is discharged, it is decompressed up to 0.04 atm.
In the prior art ozone storage methods, the ozone needs to be compressed.
Therefore, this method is inefficient because a great deal of electric power is required for absorbing ozone in the silica gel by applying pressure. Also, compressed ozone becomes reactive and the durability of the storage container becomes a matter of concern.
Further, in order to compress ozone, the costs increase for large plants and additional workers. Also, this apparatus takes a large amount of space. For these reasons, there are many unsolved problems that remain for widespread use of an ozone storage apparatus.
Additionally, the absorbent is cooled when it absorbs ozone and it is heated when it desorbs ozone. Therefore, this method causes a drastic change in temperature for the absorbent and as a result the durability of the absorbent deteriorates.
As a result of continuing research into ozone storage apparatuses and methods, the inventor has found solutions for the above-mentioned issues.
The present invention includes a method for cooling the ozone to between 0xc2x0 C. and xe2x88x9280xc2x0 C. by a cooling means and then the ozone is supplied to a storage means which is filled with a silica gel.
The present invention also discloses cooling the ozone and then supplying the ozone to a storage means filled with a silica gel by applying a pressure of 1-2 atm while maintaining the temperature of the silica gel between 0xc2x0 C. and xe2x88x9230xc2x0 C.
The method of the invention can also cool the ozone and then supply the ozone to a silica gel that is cooled between 0xc2x0 C. and xe2x88x9230xc2x0 C. for storing the ozone and oxygen can be used as a purge gas for obtaining the stored ozone.
The oxygen used as the purge gas can be compressed and supplied at 1-2 atm.
The present invention also includes filling a container having two openings with an absorbent and introducing an ozone containing gas into the container through one of the openings so as to allow ozone to be absorbed.
The present invention also includes filling an ozone absorbent in the container having two openings and introducing an ozone containing gas from one opening so as to allow the ozone to be absorbed. When extracting ozone, oxygen is supplied from another opening and the ozone is extracted from the opening through which the ozone containing gas was introduced.
The apparatus can also include an ozone absorbent in a U-shaped container having openings in the upper part and ozone is introduced into one of openings so as to allow the ozone to be absorbed.
The apparatus can also store ozone in a plurality of U-shaped containers containing absorbent and these containers can be connected in at least one of a series connection and a parallel connection so as to introduce the ozone continuously into the plurality of U-shaped containers.
This invention discloses an efficient and easy handling ozone storage apparatus and method that generates ozone when electricity costs are low, such as during the night, and then the ozone is absorbed and stored. When ozone is to be subsequently used, the ozone can be desorbed by supplying an oxygen gas.
Also, in this ozone storage apparatus and method, the container for storing an absorbent of ozone has a compact structure and this improves the efficiency of absorption and desorption.